Conventionally, for example, it has been proposed that an image forming device, such as an ink-jet printer, feeds recording sheets, such as recording paper sheets, stacked on a stacked surface of a sheet supply tray toward an image forming unit by means of a feeding roller supported to one end portion of a pivotally movable support portion. In this case, it has also been proposed that the support portion has another end portion supported to and pivotally movable about a drive shaft to which a driving force is transmitted from a motor, and the driving force transmitted to the drive shaft is transmitted to the feeding roller through a gear mechanism described below. That is, a planetary gear mechanism including a sun gear and a planetary gear is provided for transmitting the drive force to the feeding roller. The sun gear is adapted to rotate integrally with the drive shaft. The planetary gear is adapted to be swingably moved about the sun gear while maintaining engagement with the sun gear. Upon swinging movement of the planetary gear in one direction, the planetary gear comes into engagement with a gear train coupling with the feeding roller. In this case, the planetary gear is engaged with the gear train only when the drive shaft rotates in one direction. Even when the drive shaft rotates both in forward and reverse directions, the above configuration can prevent the feeding roller from rotating in a direction opposite to a feeding direction.